investigation of the best time to sample for to study of seed bank and weed density relationships in sugar beet farm land by using regressions and geostatic relations

ABSTRACT: A field experiment was conducted to investigation of the best time to sample for to study of seed bank and weed density relationships in sugar beet farm land by using regressions and geostatic relations in 2009 at the Kamal abad Agricultural Research Station in Karaj region. The Sampling from seed banks was performed before sugar beet planting and also weeds density were done by using square (50 * 50cm) quadrate in three different dates during the growing season. The results showed that the highest density of weeds in the field related to pigweed. Calculating the regression coefficient between seed bank pigweed and pigweed seedlings populations during the season showed that the relationship between seed bank and weed farm was significant (R2= .67) and the relation the follow up from the linear equation. Analysis of regression comparison between weeds seed bank, seedlings of pigweed (at first sampling time) and plant accumulative density (in tree stage sampling) showed that the first sampling time had the higher positive correlation (R2= .7) with seed bank compare to accumulative density. So the first growth stage which had an important role in weed management can be introduced as key factor for weed population from seed bank density. Generally by determination of seed bank density and species variation can be estimated in early growing season.